Heat transfer from a slot air jet impinging on a circular cylinder

Heat transfer from a slot air jet impinging on a cylinder shaped food product placed on a solid surface in a semi-confined area as investigated using computational fluid dynamics (CFD). Simulations of a cylinder in cross flow with the k-epsilon, k-omega and SST models in CFX 5.5 were compared with measurements in the literature. The SST model predicts the heat transfer better than the other models and is therefore used in this study. The distribution of the local Nusselt numbers around the cylinder for various Reynolds numbers (23,000-100,000), jet-to-cylinder distances, H/d (2-8), and cylinder curvature, d/D (0.29-1.14) was determined. The results show that the local Nusselt numbers varies around the surface of the cylinder and that the average Nusselt number and the stagnation point Nusselt number increases with increasing Reynolds numbers and surface curvature but has little dependency on the jet-to-cylinder distance. The result is Nu(m) = 0.14Re(0.65)(H/d)(-0.077)(d/D)(0.32) and Nu(s) = 0.46Re(0.59)(H/d)(-0.026)(d/D)(0.32). (C) 2003 Elsevier Ltd. All rights reserved.